Fix a couple of problems found in build testing

net/devif/ipv6_input.c

@@ -101,6 +101,7 @@
 
 #include "netdev/netdev.h"
 #include "ipforward/ipforward.h"
+#include "inet/inet.h"
 #include "devif/devif.h"
 
 /****************************************************************************

net/icmpv6/icmpv6_neighbor.c

@@ -229,8 +229,8 @@ int icmpv6_neighbor(const net_ipv6addr_t ipaddr)
       goto errout;
     }
 
-   * Continue and send the Neighbor Solicitation request only if this
-   * device uses the Ethernet data link protocol.
+  /* Send the Neighbor Solicitation request only if this device uses the
+   * Ethernet data link protocol.
    *
    * REVISIT:  Other link layer protocols may require Neighbor Discovery
    * as well.